DOVER — A man accused of attacking another patron at a Portsmouth bar last weekend — fracturing his skull and potentially causing his death — was ejected from a club in Dover approximately nine months earlier for trying to pick a fight on the dance floor, according to police records.

The incident in Dover occurred the morning of July 25, 2012, at the former RJ’s Bar and Grill, the business that was previously housed inside 83 Washington St. Dover police Officer Daniel Gebers was stationed at the bar that night with another officer.

In a police report obtained by Foster’s, Gebers wrote that at about 12:52 a.m., he saw employees escorting a man out of the bar who had attempted to start a fight on the dance floor.

“As the male came outside, he began yelling for no reason,” Gebers wrote. “As he walked past the bar windows, he (clenched) his fist and nearly punched a window. As he reached the corner of Washington Street and Central Avenue, the male grabbed a sandwich board that was there and threw it toward the building.”Gebers ran after him down the sidewalk and made the decision to handcuff him due to his “hostility.” Several of O’Neill’s friends who were in the area then became “confrontational,” according to Gebers, who received backup from two other Dover officers.

Gebers reported he could smell a “heavy odor of an alcoholic beverage” on the man’s breath.

Gebers then identified the man as Zachary O’Neill. Officers planned to take O’Neill into protective custody, but upon running a background check, they discovered a bench warrant had been issued for his arrest in Portsmouth Circuit Court.

In January 2012, O’Neill was charged with disorderly conduct by Portsmouth police following a brawl in the High-Hanover parking garage at 1:05 a.m., according to court documents. A Portsmouth police prosecutor who recounted the event last week in court said an officer was forced to pull O’Neill off another man during the street fight.

O’Neill failed to appear in court to answer to the charge, leading the court to issue a warrant for his arrest.

O’Neill was transported back to Dover Police Department headquarters, where he was processed and released on bail into his sister’s custody, according to the police report. He was given a court date of Sept. 17, 2012, to answer to the disorderly conduct charge in Portsmouth.

O’Neill never showed up, according to court records. He also skipped another hearing in October 2012, as well as a trial scheduled for Tuesday, April 2, leading the court to issue another bench warrant for his arrest.

O’Neill was finally hauled back into a Portsmouth courtroom again last week to be arraigned on a separate first-degree assault charge stemming for an incident at The Page Restaurant & Bar.

On the morning of Saturday, April 6, O’Neill allegedly attacked another 24-year-old man from behind while he was dancing on the bar’s lower level dance floor.

According to court documents, O’Neill, who was living most recently at 12 New York St. in Dover, told workers at The Page that he assaulted Joshua Krantz, of Dover, because Krantz spilled a drink on him several hours earlier.

Witnesses said O’Neill punched Krantz in the back of the head, sending him to the ground, then repeatedly struck him in the head with his fists until employees intervened.

This attack allegedly took place at 12:44 a.m., shortly before closing time. Police say O’Neill told bar staff he waited to hit Krantz until then because he knew he would get thrown out of the business and “didn’t want to ruin his night.”

Krantz, a 2006 Epping graduate, declined medical treatment and returned home to his apartment in Dover, where he was found dead several hours later. The state’s medical examiner ruled that bleeding on the brain, caused by a skull fracture, was the cause of death.

O’Neill was arraigned Wednesday morning on a first-degree assault charge. He entered no plea, and was ordered held on $250,000 cash only bail.

The medical examiner’s office has yet to rule on whether Krantz’s death was a homicide — a determination that would prompt police to elevate the charge.

O’Neill also entered a plea of not guilty Wednesday on a separate misdemeanor charge alleging he violated bail orders issued in Strafford County by committing the assault last weekend. The bail orders stemmed from a Feb. 4, 2013, traffic stop in Dover.

After being pulled over by a Dover officer, O’Neill was allegedly found to be transporting marijuana and a firearm in the car. He faces charges of driving with a suspended license (a subsequent offense), carrying a gun without a permit and possessing an undisclosed quantity of marijuana.

Dover police have declined a request from Foster’s for a copy of the police report affiliated with the traffic stop, citing the fact that his case has yet to be prosecuted. A trial date has been scheduled for June 17 in Strafford County.